The present invention generally relates to specimen analyzing apparatus represented by transmission electron microscopes and more particularly, to a specimen analyzing apparatus of the type capable of externally applying voltage or current to desired external voltage applying portions of various kinds of specimens as typified by semiconductor devices and a specimen holder for use in the specimen analyzing apparatus as well.
The specimen analyzing apparatus typified by a transmission electron microscope has high spatial resolution, for which a variety of attachable analytical functions have been developed, is very efficient as a tool for fault analysis and characteristic evaluation in various electronic devices such as semiconductor devices. As an example of the specimen analyzing apparatus, a conventional transmission electron microscope will be outlined with reference to FIGS. 2A and 2B. An electron beam 111 emitted from an electron gun 201 is accelerated by an anode 202 toward an electron lens, converged by a condenser lens 203 and then irradiated on a specimen 101. The electron beam 111 transmitting through the specimen 101 is enlarged by means of objective lens 204 and imaging lens 205 and projected on a fluorescent screen 206, so that the electron beam 111 can be visualized to enable a measurer to observe an image developing on the fluorescent screen 206. The specimen 101 is thinned in advance to a film having so small a thickness as to permit the electron beam 111 landing on the specimen to transmit therethrough and is then mounted to a specimen support (hereinafter termed a mesh 102). As shown in FIG. 2B, the specimen 101 is securely attached to the mesh 102 by using a specimen cap jig 207 and a specimen tap spring 208. Then, the specimen 101 seated on the mesh 102 is fixedly mounted to a specimen holder 106.
Typically, in measuring a specimen by using the specimen analyzing apparatus as typified by the transmission electron microscope, a specimen thinned to a film having so a small thickness as to enable a particle beam to transmit therethrough is prepared in advance of the measurement through a specimen preparation method using a specimen preparation unit such as a focused ion beam unit described in, for example, JP-A-11-108810 (Patent Document 1), that is, through a micro-sampling method. The micro-sampling method will now be described with reference to FIG. 3. In the micro-sampling process pursued in the specimen preparation unit such as focused ion beam unit, an ion beam is irradiated on an area of several tens of microns in which a desired observing portion is included, to separate a fine specimen piece 302 from a specimen 301 such as device chip or semiconductor wafer (at a in FIG. 3), the fine specimen piece 302 is picked out of the specimen by means of a manipulator 303 such as a probe (at b in FIG. 3), the picked out fine specimen piece 302 is mounted on a specimen carrier means 304 (at c in FIG. 3) and an ion beam is irradiated on the fine specimen piece 402 seated on the specimen carrier means 304 to produce a thin-film specimen including a desired observing portion 305 (at d in FIG. 3).
In conducting fault analysis and characteristic evaluation in a device by using the specimen analyzing apparatus, it is desirable for a phenomenon to be analyzed directly, which phenomenon takes place in the device being in operation under the application of external voltage to a specimen. For directly analyzing the phenomenon developing in the device with a desired portion of the specimen being connected to an external voltage power supply, JP-A-06-310069 (Patent Document 2) describes a method according to which an electrically conductive pattern is formed in advance on a specimen stand forming a part of specimen holder and a semiconductor specimen is mounted having its voltage terminal set in register with the conductive pattern on the specimen stand. Further, JP-A-10-185781 (Patent Document 3) describes a method in which a specimen per se is provided with an electrode, a current conduction terminal corresponding thereto is provided on a specimen holder and the specimen is pressed against the specimen holder by a specimen cap so as to be fixedly mounted. In addition, methods have hitherto been known including one for directly attaching a chip or a fine conductor to a thin-film specimen as disclosed in JP-A-2003-35682 (Patent Document 4) and another for applying external voltage to a specimen through many probes or styluses brought into contact with the specimen.